logging: Public API for setting timestamp, severity, etc. on Entry

[zbjornson]

I can't find a public API for setting the metadata fields like timestamp and severity on a log entry.

It works to do var entry = log.entry(...); entry.severity = "INFO";, which is similar to what's done internally in Log.assignSeverityToEntries_, but I think there should be an options object argument in the Entry constructor.

[stephenplusplus]

An Entry already takes two objects, the first for the resource details, the second for the data.

We can change the resource argument to metadata:

// before
var entry = log.entry({
  type: 'gce_instance',
  labels: {
    zone: 'global',
    instance_id: '3'
  }
}, {
  delegate: 'my_username'
});

entry.httpRequest = {...};

// after
var entry = log.entry({
  httpRequest: {...},
  resource: {
    type: 'gce_instance',
    labels: {
      zone: 'global',
      instance_id: '3'
    }
  }
}, {
  delegate: 'my_username'
});

Which do you prefer?

// @callmehiphop for thoughts

[callmehiphop]

Could we just add an optional metadata field to the resource itself?

var entry = log.entry({
  type: 'gce_instance',
  labels: {
    zone: 'global',
    instance_id: '3'
  },
  metadata: {
    httpRequest: {},
    timestamp: Date.now()
  }
}, {
  delegate: 'my_username'
});

Or is that too weird?

[zbjornson]

Of the two, I think I like @stephenplusplus's proposal. The "resource" is already a bit confusing in nature, so it's nice to keep it explicitly separated. @stephenplusplus's is a breaking change though unless it's decided to keep supporting (resource, payload) in addition to the new ({resource, metadata}, payload).

[zbjornson]

I was also thinking (resource, options, payload), like

entry(
  {type: type, labels: {}},
  {severity: severity},
  {message: "server up"}
)

[stephenplusplus]

The only downside of the three arguments is that both resource* and options are optional, so if we only receive 2 arguments, we couldn't safely detect which kind it is. Breaking change is unfortunate, but not a deal breaker.

*resource is optional because it can be specified at the time of the call to entry.write to apply to all of the entries given.

[zbjornson]

Good point! Then my vote stays with ({resource, metadata}, payload). :)